diff --git a/lib/flash_internal.c b/lib/flash_internal.c
index 576053c..2a1a093 100644
--- a/lib/flash_internal.c
+++ b/lib/flash_internal.c
@@ -122,7 +122,7 @@ int32_t flash_internal_write(uint32_t address, const uint8_t *buffer, size_t siz
 	if (address < FLASH_BASE) {
 		return -3;
 	} else if ((uint32_t)&__flash_end >= FLASH_BASE && (address + size) > (uint32_t)&__flash_end) {
-		return 4;
+		return -4;
 	} else if ((uint32_t)&__flash_end < FLASH_BASE && (address + size) > (FLASH_BASE + DESIG_FLASH_SIZE * 1024)) {
 		return -5;
 	}